Zarrella says the right Twitter strategy depends in part on what your goals are. Want to accumulate as many followers as possible? Then tweet a lot: Twitter’s A-listers — those with the most followers — tweet an average of 22 times a day, and more tweets generally lead to more followers. But if your goal is to drive more traffic to your site, you should show a little more restraint; accounts that share two or more links an hour show a dramatically lower clickthrough rate than those who share no more than one.

It’s an inexact science, but at least it’s an attempt at science where so much social media strategy is driven by intuition. (Zarrella complains about the the “unicorns and rainbows” strategy: “Love your customers, hug your followers, engage in the conversations. It sounds like good advice, and it’s hard to disagree with,” he says. “But generally, it’s not based in anything substantial.”)

After collecting more than two years of data, Zarrella shared his findings Tuesday in a webinar called “The Science of Timing.” That science is less about when and more about when not — what he calls “contra-competitive timing.” The trick is to reach people when the noise of the crowd has died down.